The lifestyle maven let slip her potentially guilty pleasure in a New York Times story entitled "What Martha Stewart Can't Travel Without." Her list of must-have travel accessories included Rimowa luggage, which can cost $600 or more per piece, and "three iPads."

"One's just for books, one's for TV show series and one's for movies," Stewart said explaining her iPad trifecta.

When told about Stewart's "shahtoosh" comment, a top official at the United States Fish and Wildlife Service, said that if, in fact, Stewart owns an shawl that is actually made from shahtoosh: "That would be an issue."

Americans cannot own a shahtoosh shawl or other shahtoosh product "because it was illegally brought into the United States," said the official, Edward Grace, acting assistant director for law enforcement for the FWS.

And "You can't travel out of the United States with it, and it can't be going into the United States," Grace said.

He noted that when Fish and Wildlife Service agents encounter a shawl they suspect is made from shahtoosh, the first test they do is to see if the garment can pass through a ring.

"Shahtoosh is pretty much the only fabric that you can pull the entire shawl, which is several feet long, through a wedding ring," Grace said.

In response to a request for comment, Stewart provided CNBC an emailed statement. "I should have said shahtoosh-like, which is what I meant," Stewart said.

"I am fully aware of the endangered species category, and no one is more of an animal rights advocate than I am," Stewart said. "I live on a farm with over 250 animals and would never support endangering any animal."

After CNBC reached out to Stewart's spokeswoman to ask about the Times interview, the newspaper updated its online version of the story with the following comment.

"[Update: After this article was published, Ms. Stewart hastened to clarify that the shawl is made from cashmere and is not an actual shatoosh, which uses the hair of an endangered Tibetan antelope.]" (sic)

Prosecutors said Stewart dumped that stock after her stockbroker's assistant tipped Stewart to the fact that ImClone's CEO, Samuel Waksal, was trying to sell some of his own shares. Stewart had claimed to authorities that she sold the stock only because of an earlier agreement with her broker to sell it if the price fell below a certain threshold. But a jury didn't buy that explanation.

Shahtoosh, which means "king of fine wools" in Persian, is made from the hair of Tibetan antelopes that are also known as "chiru."

Chiru, are "rare and highly protected," according to the Fish and Wildlife Service.

Grace told CNBC that years ago many wealthy people bought into a "myth" that herdsman collected hair to make shahtoosh from bushes that Tibetan antelopes had rubbed up against.

"People didn't realize that hair is from the underbelly of the Tibetan antelope," which had to be killed for the hair to be collected, Grace said.

"They were pretty much being machine-gunned down on plateaus," Grace said.

China Photos | Getty Images

A forest policeman of Kekexili Nature Reserve with Tibetan antelopes at a wild animal rescue center on April 21, 2005 in Chengduo County of Qinghai Province, China.

He said that articles about the slimy shahtoosh trade in magazines such as Vanity Fair and Cosmopolitan exposed the myth of how the fur was collected as a lie.

"People understood the animals were being killed," Grace said.

A 2001 Vanity Fair article, entitled, "O.K., Lady, Drop the Shawl," detailed a widespread probe into shahtoosh ownership among the East Coast elite.

"More than one hundred socialites and celebrities, including fashion icon Nan Kempner, supermodel Christie Brinkley, and arts patroness Beth Rudin DeWoody, had hand-delivered to them at their country houses or Manhattan apartments by U.S. marshals in July: subpoenas 'for person and documents or objects,' ordering them to testify before a grand jury sitting in Newark and to bring with them 'any and all shahtoosh shawls, other shahtoosh items, and items made from the Tibetan antelope, chiru or ibex,'" the article said.

"The demand for shahtoosh has already pushed the chiru to the brink of extinction. The antelope must be killed for the fur to be collected, and it takes around four chiru to make a single shawl," the article said.

Nuzhat Saadia Siddiqi, an environmentalist and activist, told The Guardian: "The prestige factor may be high with shahtoosh, but it is false prestige, standing on the carcasses of dead animals. Anyone wearing, buying, selling, gifting shahtoosh shawls should be ashamed of themselves."

Grace told CNBC that importers of shahtoosh face prosecution on charges that carry potential prison sentences of as long as five years.

He said that individuals who are found to possess shahtoosh during a customs check at U.S. airports are typically offered the opportunity to abandon it to the federal government.

"It ends there, if they have no knowledge that it was made from an endangered species," Grace said.

"On the chance that they had some possible knowledge, they may get a ticket," he said.

Asked what Stewart should do with her shahtoosh, Grace said, "If I were her, I would turn it over to the U.S. Fish and Wildlife Service."

Then, he added, "we could identify if it's [actually] shahtoosh, if it's illegal to have."